In recent years, with regard to liquid crystal display electronic devices such as a personal computer or car-navigation system and the like, liquid crystal display devices with backlights are widely used. As a light source of this backlight, a fluorescent lamp such as a cold cathode fluorescent lamp and the like are used.
The liquid display devices of this kind comprise, as shown in FIG. 15, a liquid crystal unit (2), a lamp unit (6) provided with cold cathode fluorescent lamp (4), liquid crystal control unit (8), inverter unit (10) and connector (12). These devices are electrically connected by virtue of electric cords as shown in this drawing, and are mounted on personal computers or car-navigation systems. The inverter unit (10) is supplied with a power source by virtue of the connector (12), and the liquid crystal control unit (8) is built to input the power source and control signal through the connector (12). Furthermore, a product of an integrally combined liquid crystal unit and liquid crystal control unit has been developed.
When a liquid crystal display device is designed to be of a small size and a thin unit, if a lamp unit and inverter unit are separately built, such a unit is extremely inconvenient, and is not fit to a small size unit of a liquid crystal display device. Moreover, when the lamp unit and the inverter unit are separately built, a high voltage supply electric wire for connection of the inverter unit and the lamp unit tends to become long, and safety is compromised which is a problem.
When the high voltage electric wire becomes longer, electric current leaks due to a floating capacity between grounds which results in a drop of voltage before the voltage reaches a lamp portion. In this case, a problem occurs as a requirement of readjustment of the inverter unit becomes necessary.
An object of the present invention is to solve the foregoing problems.